Study On The Positive And Inversion Application Of Transient Electromagnetic Method Of Water-containing Abnormal Bodies In Mine Under The Influence Of Low-resistance Layer Shielding

As the future development trend of coal mining industry,the complex geological mining conditions are a difficult problem that must be solved in the process of coal intelligent precision mining construction,especially the mine water damage accident not only seriously restricts the improvement of the mining level,but also poses a great threat to the safe and efficient production of the mine.The transient electromagnetic method is widely used to detect water-bearing abnormal sands and other abnormal geological structures in coal-rock bodies because of its sensitivity to low resistance,high detection accuracy and high construction efficiency.However,the current transient electromagnetic research and practical application shows that when we want to detect the water-containing abnormal body above or completely covered by the lowimpedance layer,the detection accuracy of the water containing water under the lowimpedance shield layer will be greatly reduced.Because the geological environment of coal mining in China is extremely complex,the problem of mine transient electromagnetic exploration affected by the shielding effect of low blocking layer will become more and more serious with the trend of coal deep mining and precision mining in our country.Therefore,through the positive numerical simulation of transient electromagnetic and the inversion algorithm,this paper studies the problem of watercontaining abnormal bodies affected by low-resistance shielding in underground fullspace transient electromagnetic exploration.First of all,using COMSOL software simulation in the full space conditions to simulate the existence of low-resistance shielding layer above the water-bearing abnormal body,by analyzing the model’s transient electromagnetic response characteristics,found that the low-impedance shielding effect will not only affect the reaction of the water-bearing abnormal body below to the transient electromagnetic field,but also make the secondary field propagation more slow,extendthed diffusion time.Therefore,in the field application of transient electromagnetic in the mine,when the low resistance shielding effect may occur through on-site monitoring or geological data analysis,we should extend the observation time appropriately to ensure that the observed data are more accurate.Secondly,using MATLAB to write an inversion program to try out 6 typical stratospheric geoelectric models,to study the effect of low-resistance shielding effect on transient electromagnetic inversion results,and to introduce genetic algorithms to overcome the highly nonlinear in mine transient electromagnetic inversion,relying on the initial model and other difficulties,the inversion method was optimized.The results of the rapid inversion of the smoke ring show that the low-resistance shielding effect will also have a negative effect on the inversion effect,and the nonlinear inversion based on the genetic algorithm shows that the genetic algorithm can not only effectively reduce the effect of low-resistance shielding effect,but also improve the inversion accuracy.Finally,the research results of this paper are verified by using field data.By prolonging the observation time of the data and optimizing the inversion method by using the genetic algorithm,the(1)anomaly from the(1)to the lower layer(2)abnormal region was successfully explored.This article has 41 pictures,10 tables,81 references.